WASTE GAS PURIFYING CATALYST AND WASTE GAS PURIFYING METHOD USING THE CATALYST

摘要

PROBLEM TO BE SOLVED: To further improve the durability of a waste gas purifying catalyst of the NOx occluding and reducing type by suppressing the sulfur poisoning of an NOx occluding material. SOLUTION: The waste gas purifying catalyst of the NOx occluding and reducing type is divided into a first catalyst positioned on the upstream side of a waste gas and a second catalyst on the downstream side. The NOx occluding material to be deposited on the first catalyst adsorbs sulfur more easily and detaches sulfur more difficultly than the NOx occluding material to be deposited on the second catalyst. Further, a space is left between the first catalyst and second catalyst to further enhance the NOx occluding capacity.